The present invention relates to a semiconductor device having a touch panel controller operable to control a touch panel and a display driver operable to control a display panel and for example, a technique useful in application to a portable terminal having, as an input device, a touch panel superposed on a display panel.
In a touch panel supporting a multipoint touch according to a mutual capacitance technique, for example, drive electrodes and detection electrodes are arranged to intersect with each other at e.g. right angles with dielectric interposed therebetween; the cross-coupling capacitance of each intersection of the drive and detection electrodes makes a node capacitance. When a capacitance produced by a finger or hand is brought into the vicinity of such a node capacitance, the mutual capacitance of the node decreases by an amount corresponding to a combined capacitance resulting from the approach of the finger or hand. To detect the node capacitance which the change in mutual capacitance has been caused on, the touch panel controller sequentially activates the drive electrodes by use of pulses, integrates, as a signal, a change in voltage developed on each of the detection electrodes capacitively coupling with the drive electrodes, and acquires a signal resulting from the integration for each detection electrode as a signal corresponding to a change in mutual capacitance among the node capacitances arranged so as to form a matrix. A controller which drives a touch panel and detects signals by means of the mutual capacitance technique like this has been already disclosed by e.g. U.S. Patent Application publication No. US2007/0257890A1.
In a portable terminal or the like, a touch panel is arranged over a display panel, which functions as an input device in fact while acquiring data including the correspondence between a display position of a displayed menu and touch coordinate position. As a driver LSI having a display driver operable to perform the drive control of a display panel in addition to a touch panel controller used for drive control of such a touch panel, a driver LSI having a calculation circuit operable to calculate a touch position coordinate from detection signals detected by the touch panel controller has been available.
One example of such driver LSI is described in Japanese Unexamined Patent Publication No. JP-A-2011-13996.